Disc PVP - offensive "rotation"

Started an arena team a few days ago, and have been pretty successful through a 1500 rating. I usually just try to stay alive while being trained while my arms warrior partner kills our opponents - it's worked OK so far.

I'm starting to read up on strats for disc priests in arena, and have a few Q's on my offensive priorities.

I've read from folks that have obtained the Gladiator title, our most powerful offensive spell is dispell magic. How so? Is this something you spam on your opponents until all their buffs are gone, or is there more to it?

I've also read that DOTs are not a good idea and just waste mana. I've probably done 50 matches so far, and have been OOM in maybe 5. I'm usually dead or we've won the fight long before I can run out of mana. I usually try to DOT as much as I can (while I'm still alive) to wear down our opponents as much as I can before I get killed - leaving my team mate with weakened or dying opponents to finish off. Should DOTs be used in arena matches?

I've read some people just spam Mind Spike and SW D as their only offensive spells (besides dispel magic, if you call that offensive). Is this a good idea?